1. Field of the Invention
The present invention concerns an ignition system for an internal combustion engine, and more particularly, an alternating current based ignition system in which a computer, in which a motor-specific data recognition field ("look-up" table) is stored and which is provided by sensors with operating parameters, controls the duration of the alternating ignition current and the ignition coil energy.
2. Description of the Related Art
Ignition systems using alternating current ignition are known as exemplified by DE 39 28 726. In order to adapt the ignition system to the various load conditions of the internal combustion engine, the firing time of the high frequency alternating ignition current can be altered to effect the bum time of the ignition spark. With this known type of ignition system, the spark current amplitude is constant during the firing time. The amplitude must be selected to be of sufficient magnitude, such that under all load conditions of the motor a guaranteed ignition is insured. The effective voltage amplitude necessary for ignition under various load conditions of the internal combustion engine varies greatly. This means that, as a rule, the energy supplied for the ignition in known systems is too large. This increases sparkplug wear and increases electricity usage during the starting and running of the motor.
It is an objective of the present invention to provide an alternating current based ignition system for internal combustion engines, which operates more efficiently under changing operating conditions.